Fraction collector with adjustable tray

ABSTRACT

A fraction collector comprising a movable tray is provided. The movable tray may be attached to the fraction collector support system in a variety of ways and adjusted without adjusting the parts of the fraction collector support system. The moveable tray may be stably attached to the fraction collector support system by either fixed or removable pegs, as well as by channels. In an exemplary embodiment, a mechanized lift is used to adjust the position of the movable tray.

REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/221,589, filed Sep. 8, 2005, now U.S. Pat. No. 7,361,269 thedisclosure of which is incorporated herein by reference in its entirety.U.S. patent application Ser. No. 11/221,589 claims the benefit of U.S.Provisional Patent Application Ser. No. 60/609,105, filed Sep. 10, 2004the disclosure of which is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention is directed to a collection apparatus and methodsfor use of the collection apparatus. The present invention relates toliquid handling devices and more particularly to fraction collectors.The devices of the present invention may be used for chromatographicseparations, sample purifications, and more particularly, for highthroughput purification of samples from a chemical library.

BACKGROUND

Fraction collectors are well-known devices intended for collectingliquid samples originating from slow-flowing sources having variableliquid compositions. Fraction collectors are typically used inchromatographic separations such as high performance liquidchromatography (HPLC), gas chromatography (GC), supercritical fluidchromatography (SFC), column chromatography, and liquid-liquidseparations, and for the collection of distillates from variousdistillation processes. The size of each individual sample or fractiondispensed by the fraction collector is determined by conventionalmeasuring equipment such as a timer, a drop counter, a level sensingdevice, or by a variety of spectrophotometric methods. Fractioncollectors typically sequentially align a dispensing head, carry asample delivery conduit or tube over individual collection vessels partof an array of collection vessels, and deliver sample to collectionvessels.

Fraction collectors may be broadly categorized into two groups. Thefirst group includes fraction collectors in which a plurality ofcollection vessels are mounted on a generally circular turntable. Thesefraction collectors are commonly called “turntable collectors.” Theturntable collectors all generally operate to fill a plurality ofcollection vessels by the combination of a rotatably mounted turntableand a rotatably mounted arm carrying a dispensing head. The dispensinghead is typically aligned over a single collection vessel, the liquid isdispensed into the collection vessel, and the turntable then rotates toalign with another collection vessel. In turntable collectors, theplurality of collection vessels are typically arranged in a concentriccircular or spiral pattern. In order to manipulate the dispensing headover collection vessels in different circles of a concentric pattern orwith an expanding or contracting spiral pattern, the rotatably mountedarm moves to align the dispensing head with each of the individualcollection vessels in the arrangement.

The second group of fraction collectors includes collectors with thecollection vessels arranged in a grid pattern on a stationary stage, anda dispensing head manipulated in either a 2-dimensional plane or in allthree dimensions to selectively dispense liquid into the individualcollection vessels. Fraction collectors in the second group are commonlycalled “X-Y collectors.”

The two groups of fraction collectors each have distinct advantages. Forexample, when handling a large number of liquid collection vessels,fraction collectors with rectangular grid patterns more effectively usebench space. X-Y collectors are also better suited to handling largescale collection vessels than are the rotatably mounted turntables.Furthermore, X-Y collectors may be adapted to popular standardizedreceptacle plates, such as microtiter plates, or other standard orcustom arrangements. In contrast, turntable-type fraction collectors maybe more advantageous when used in high resolution liquid chromatographyas they require shorter attachment tubing between the slow-flowingsource and the dispensing head, thus limiting diffusional re-mixing ofthe separated components within the liquid flow and resulting in betterseparation.

Both X-Y and turntable fraction collectors must be adjusted to fit thecollection vessels used for sample collection, which commonly come invarious sizes. Generally, vertical adjustment of the fraction collectorhas typically been done by either manual adjustment of the legs orincorporation of a vertical adjustment (Z-axis) of the dispensing head.The first method, utilized in some X-Y collectors, allows for manualadjustment of the height of the dispensing head by removing the legs ofthe base of the fraction collector and putting on longer or shorter legsas desired. However, while this method can be effective, if the legs ofthe base are adjusted manually, the racks containing the collectionvessels need to be removed during adjustment, as the legs can only beadjusted individually. Furthermore, it is difficult to balance thecollection bed during the adjustment, creating the opportunity forspillage to occur. Moreover, manual adjustment requires realignment ofthe dispensing head with the collection vessels and collection bed,introducing additional steps that could damage the fraction collectionapparatus. As fraction collectors have become more advanced, thetolerances have become tighter, and therefore manual adjustment of thedispensing head assembly threatens to damage some of the fragileelectrical parts.

In addition, manual vertical dispensing head adjustment may knock thedispensing head out of horizontal alignment, causing the liquidfractions to miss the sample collection vessels. This can result in losttime in cleaning up the liquid, damage to the instrument, or present ahazardous environment for the operator, depending on the contents of theliquid. Furthermore, when a dispensing assembly is knocked out ofalignment, the precision alignment procedures required to realign theassembly can be very time consuming.

Incorporation of a vertical adjustment (Z-axis) axis into the dispensinghead is known in the art. However, fraction collectors with a Z-axisrequire complex mechanics, and sometimes software, in order to get thedispensing head to move reliably and precisely in all three directions.These complex mechanics often add both size and cost. Furthermore,because collection vessels used in a single fraction collection run arecommonly of uniform size, a dispensing head that moves in a verticaldirection is often unnecessary.

Regardless of whether the fraction collector is an X-Y collector or aturntable collector, it is of primary importance in the design that themechanism for aligning the dispensing head and collection vessels be assimple and as sturdy as possible, while being reliably capable ofprecisely positioning the dispensing head over sequential collectionvessel. Although many fraction collectors known in the art can reliablyand precisely position the dispensing head over a sequential collectionvessel, many are quite complex and therefore not only expensive butdifficult to adjust and maintain. In particular, known fractioncollector arrangements may include dispensing head adjustment mechanismsthat are extremely complicated and delicate.

Therefore, a need exists for a fraction collector that reliably andprecisely aligns a dispensing head and collection vessel without addingsignificant cost or fragility.

SUMMARY OF THE INVENTION

This invention relates to a new device for adjusting the distancebetween the dispensing head and the collection vessel on a fractioncollector. More specifically, this invention relates to a bed on afraction collector that can be adjusted without adjusting the legs ofthe fraction collector. Because the bed of the fraction collector can beadjusted, there is no need for a Z-axis on the dispensing head.

In one embodiment, the invention provides for a fraction collector thatincludes a support system, a carriage movably supported by the supportsystem, an extension arm attached to the carriage, a dispensing headmoveably attached to the extension arm, wherein the dispensing head andcarriage can move along the support system in a first plane, and acollection bed moveably connected to the support system wherein thecollection bed may be moved in a second plane perpendicular to the firstplane without adjusting the support system.

In certain embodiments, the invention may comprise a method for usingthe fraction collector by determining a proper displacement of thecollection bed from the dispensing head, aligning the collection bedwith the support system at the proper displacement, and stably attachingthe collection bed to the support system.

In one embodiment of the present invention, the fraction collectorincludes a support system, a carriage including an extension arm with adispensing head connected to the support system, wherein the dispensinghead and carriage move together in a single plane, and a collection bedconnected to the support system such that the collection bed isadjustable in a direction perpendicular to the single plane. In thisembodiment, the support system for the fraction collector comprises leftand right legs with leg bases and a front and top brace. Generally thesupport system supports both the carriage and the collection bed. Insome embodiments, the single plane is an X-Y plane level with andparallel to a support surface such as a bench or table and the directionperpendicular to the single plain is the Z direction. Typically, thecollection bed will be capable of holding collection vessels of varioussizes and shapes with or without a system of racks.

In another aspect of the invention, the collection bed of the fractioncollector is made of a tray having two side edges and front and rearedges. Attached to the collection bed are collection bed arms whichextend to attach the collection bed to the support system. In oneembodiment of the invention, the support system has a series of pegs inthe right and left legs and the collection bed arms have anchor pointsspaced in a complementary fashion to the pegs in the legs of the supportsystem. The collection bed may be vertically adjusted by raising orlowering the collection bed and locking the collection bed in place onthe support system through the pegs and anchor points on the collectionbed arm. In alternative embodiments, the anchor points on the collectionbed may be slots or holes and the pegs in the legs may be fixed orremovable.

In another embodiment, the collection bed may be vertically adjusted byraising or lowering the collection bed and locking the collection bed inplace on the support system through a series of peg holes in the rightand left legs, and anchor holes on the collection bed arms such thatremovable pegs may be inserted through the anchoring holes and into thepeg holes to secure the collection bed in place.

In still another embodiment, the collection bed arms are angularlydisposed from the tray of the collection bed by an angle, such that whenthe tray is tipped back the whole collection bed is verticallyadjustable. In this and other related embodiments, the right and leftlegs of the support system may have grooves or notches for retaining thevertical adjustment of the collection bed. Furthermore, in certainembodiments, the rear edge of the collection bed tray may be shaped tofit into the grooves or notches, or the rear edge of the collection bedtray may have an attached complementary shape to the grooves or notchessuch that the complementary shape precisely fits into the groove ornotch.

In yet another aspect of the invention, the right and left legs of thefraction collector support system may have exterior or interior channelscapable of holding the collection bed at a level orientation when thecollection bed arms are inserted into them.

Other embodiments of the invention may include a fraction collector fordispensing liquid from a dispensing head into collection vessels carriedon a collection bed, the fraction collector includes a support system, acarriage including an extension arm with a dispensing head connected tothe support system, wherein the dispensing head and carriage movetogether in a single plane, and a collection bed connected to thesupport system such that the collection bed is adjustable by way of liftmovement.

In other contemplated embodiments of the invention, the collection bedmay not be attached to the apparatus and instead may rest upon or fullyintegrate a stage that can be raised or lowered manually, via hydraulicmethods, or with a motorized screw mechanism. In such embodiments, thecollection bed needs will be reliably and precisely aligned with thedispensing head on the apparatus using markings on the fractioncollector and collection bed, positioning lasers on the apparatus,and/or markings on both the fraction collector and support on which thefraction collector rests, such as a laboratory bench.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a fraction collector demonstrating theuse of pegs on the legs of the fraction collector.

FIG. 2 is a perspective view of a fraction collector demonstrating theuse of peg holes in the legs of the fraction collector.

FIG. 3 is a perspective view of a fraction collector demonstrating theuse of exterior channels in the legs of a fraction collector.

FIG. 4 a perspective view of a fraction collector demonstrating the useof interior channels in the legs of a fraction collector.

FIG. 5 is a perspective view of an alternative style collection bed.

FIG. 6 is a perspective view of a mechanized style collection bed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated by the embodiment of FIG. 1, the fraction collectordevice 100 comprises a vertically adjustable collection bed 101 in agiven position under a dispensing head 150. As one of skill in the artwill understand, this given position may be in any of a range ofpositions. As a non-limiting example, the given positions may beappropriate for racks containing collection vessels of known size. Inother embodiments, the given position may be adjustable along acontinuum allowing the use of custom collection vessels. The dispensinghead 150 is moveably mounted on an extension arm 160 that is in turnmoveably mounted on a carriage 170. In the embodiment demonstrated byFIG. 1, the dispensing head 150 is capable of movement along theextension arm 160 in a Y-direction, and the extension arm 160 is capableof movement in an X-direction. The skilled artisan understands that theX and Y directions are arbitrarily assigned and not meant to belimiting. Embodiments where the dispensing head 150 moves in theX-direction and the extension arm 160 moves in the Y-direction areanticipated.

The fraction collector 100, as shown in FIG. 1, is supported by a leftleg 180, a left leg base 200, a right leg 190, and a right leg base 210.As will be understood by one skilled in the art, the bases of the legsmay be any shape adequate to stabilize the legs. Although a certainshape of base is demonstrated in the figures, the base is not meant tobe so limiting. The two legs are connected by a top brace 220 and afront brace 230. Although the embodiment of FIG. 1 demonstrates the topbrace 220 and front brace 230 as permanently connecting the two legs,further embodiments anticipate the top brace 220 and the front brace 230as removably connected to the two legs, such as through the use ofscrews. Additional embodiments contemplate the front brace extending tothe support surface. In some embodiments, the legs, leg bases, andbraces will form a support system for the fraction collector. In stillother embodiments, it is contemplated that the support system will notinclude a front brace.

The carriage 170 is mounted behind the front brace 230 by one of anumber of methods well known to those of ordinary skill in the art. Thecollection bed 101 has a tray area 102 where the racks 240 are situated,as shown, or where individual collection vessels may be arranged using asystem other than the rack system. The collection bed 101 further hastwo collection bed arms 110, that extend from the tray area of thecollection bed 101, and provide attachment of the collection bed to theleft 180 and right leg 190. The collection bed arms 110 allow forvertical height adjustment of the collection bed 101.

A number of specific devices for attaching the collection bed arecontemplated as demonstrated by FIGS. 1, 2, and 3. In FIG. 1, both theleft leg 180 and the right leg 190 have a series of front pegs 140 andrear pegs 145. As shown, all of the pegs are in fixed positions, howeverthe skilled artisan will appreciate that the pegs may also be moveable.FIG. 1 shows the collection bed arms as having front anchoring points120 and rear anchoring points 130. The collection bed 101 is attached tothe left leg 180 and right leg 190 by engaging the front anchoringpoints 120 with the front pegs 140 and the rear anchoring points 130with the rear pegs 145. The front pegs 140 and the rear pegs 145 aresituated on the left leg 180 and right leg 190 such that the collectionbed 101 is level when all the anchoring points are engaged by thecorresponding pegs.

In the embodiment of FIG. 1, vertical adjustment of the collection bed101 is made by manually disengaging the anchoring points 120, 130 andmoving the collection bed up or down, depending on the desired location,and then reengaging the anchoring points 120, 130 with the pegs 140, 145at the new location.

The embodiment of FIG. 2 demonstrates another way of attaching thecollection bed 101 to the legs 180, 190 of the fraction collector 100.FIG. 2 shows the collection bed arm 110 as having front 125 and rear 135anchoring holes, while the left leg 180 and right leg 190 have front 142and rear 148 peg holes. The peg holes and anchoring holes are positionedsuch that the front anchoring holes 125 will align with the front pegholes 142 and the rear anchoring holes 135 will align with the rear pegholes 148 when the collection bed 101 is level. When the anchoring holesand peg holes are aligned, movable pegs 141 may be inserted to fix thecollection bed 101 to the legs. Although the embodiment demonstrates pegholes and pegs cylindrical in shape, one skilled in the art willunderstand that the pegs may be any shape, including squares,rectangles, semi-circles and the like. In alternative embodiments, pinswill be placed through the anchoring holes and peg holes to fix thecollection bed 101 to the legs.

FIG. 3 demonstrates yet another embodiment of the present invention. InFIG. 3, left leg 180 and right leg 190 of the fraction collector havemounted exterior channels 250. In certain embodiments, the exteriorchannels 250 will not be mounted, but will be an integral part of thelegs. In the embodiment of FIG. 3, the collection bed arms 110 areinserted into the exterior channels 250 in order to hold the collectionbed in a fixed position. The exterior channels 250 are positioned on thelegs, at various heights, such that the collection bed 101 will be levelwhen attached to the fraction collector 100. Numerous channel sizes andspacings may be envisioned by one of ordinary skill in the art in orderto achieve a greater or lesser range of height adjustment for thecollection bed 101. For example, the exterior channels 250 may bearranged according to collection vessels currently known to exist in theart. It is not an object of this invention to be limited by theillustrated scale of the positions or number of positions shown in thefigures.

The embodiment of FIG. 4 shows an arrangement similar to that in FIG. 3.FIG. 4 demonstrates interior channels 260 recessed into the left andright legs 180, 190 of the fraction collector 100. In this case, thecollection bed arms 110 are inserted into the interior channels 260. Theinterior channels 260 are positioned on the legs, at various heights,such that the collection bed 101 will be level when attached to thefraction collector 100. Once again, the positioning of the interiorchannels are not meant to be limiting. Furthermore, the skilled artisanwill understand that although the exterior channels demonstrated in FIG.3 and the interior channels demonstrated in FIG. 4 are shown onperpendicular sides of the legs, the channels may be on any side of theleg, as long as the collection bed arms are adapted. In someembodiments, the interior channel will extend through the leg. In otherembodiments, the interior channels may be on a parallel side of the leg.If the interior channels are on a parallel side of the leg, thecollection bed arm will need to include at least one projection forconnection.

Although FIGS. 1-3 demonstrate attachment of the collection bed arm 110on the outside side of the leg, it is also contemplated that the locusof attachment using any of the above-mentioned attachment devices couldbe also on the inward facing portion of the legs. Moreover, one of skillin the art will understand that different styles of legs may be used inplace of legs 180, 190. In certain embodiments, the legs may encompasslegs with grooves, as well as legs having other styles. In someembodiments, both edges of the leg will have cutouts or other types ofnotches. In other embodiments, only one side of the leg will havegrooves or notches. The skilled artisan will understand that the number,size and side of the attachment devices are not meant to be limited bythe illustrated scale of the positions or number of positions shown inthe figures.

FIG. 5 shows an embodiment of an alternate style of collection bedassembly 300. In the embodiment of FIG. 5, the leg of the support systemincludes grooves or notches 280, that are able to receive a rod 330. Arear edge 290 of the collection bed 300 may rest against legs 180, 190possibly in grooves or notches to further support the collection bed101. As in FIG. 5, the collection bed arms 320 are angularly disposedfrom the plane of the collection bed. The arms 320 can either beattached by the rod 330 as shown in FIG. 5, looped, or a rod may onlypartially extend from one leg to the other. As one of skill in the artunderstands the extension of the rod may vary in alternativeembodiments. The rod can either be short or long while still keepingwithin the spirit of the invention.

In the embodiment of FIG. 5, the alternate style collection bed 300 isvertically adjusted by raising the front portion of bed 300 enough tofree the rear edge 290 from the legs 180, 190 and to release the rod 330from the grooves 280 and then sliding the collection bed 300 up and downthe legs to the desired position. In addition to the grooves 280 asshown in FIG. 5, other embodiments are envisioned. For example, a seriesof notches that receive a complementarily shaped portion of the rearedge of the collection bed tray is contemplated. Furthermore, thenotches could also be locks designed to accept a complementarily shapedkey.

Mechanized embodiments of the invention are contemplated. For example,the fraction collector may include a collection bed with a hydrauliclift. As demonstrated by FIG. 6, the fraction collector 500 may comprisea collection bed 510 with a screw-driven lift 520. The screw-driven lift520 may include a screw 530 and an expandable lattice 540. Although theembodiment shown in FIG. 6 demonstrates two screw driven lifts, theskilled artisan will understand that any number of lifts, as long asthey can function with a fraction collector, may be used. It iscontemplated that embodiments comprising a hydraulic lift or ascrew-driven lift may be motorized with either an automatically drivensystem or a manually driven system. In the mechanized embodiments, thecollection bed may not be attached to the fraction collector. Instead,the collection bed may rest upon or fully integrate with a stage thatcan be raised or lowered manually, via hydraulic methods, or with amotorized screw mechanism. In such embodiments, the collection bed needsto be reliably and precisely aligned with the dispensing head on theapparatus. Precise alignment could be carried out via markings on theapparatus and collection bed, positioning lasers on the apparatus,and/or with markings on both the apparatus and support on which theapparatus rests, such as a bench. Because mechanized versions add alayer of complexity to the vertically adjustable collection bed, and maybe impractical in certain situations and because mechanized versionsutilize mechanics well understood by the skilled artisan, theseembodiments will not be further described.

While embodiments of the foregoing invention have been described in somedetail and by way of illustration and example to provide clarity andunderstanding, it should be understood that certain changes andmodifications can be made therein in accordance with ordinary skill inthe art without departing from the invention in its broader aspects asdefined in the following claims.

What is claimed is:
 1. A fraction collector, comprising: a supportsystem; a carriage moveably supported by the support system; anextension arm connected to the carriage; a dispensing head moveablyconnected to the extension arm; wherein the dispensing head and carriagecan move relative to the support system in a first plane; a mechanizedlift; and a collection bed mounted on the mechanized lift, wherein thecollection bed can be moved in a second plane perpendicular to the firstplane using the mechanized lift without moving the support system. 2.The fraction collector of claim 1, wherein the support system comprises:a left leg; a right leg; and a top brace.
 3. The fraction collector ofclaim 2, wherein the support system further comprises a front brace. 4.The fraction collector of claim 1, wherein the collection bed comprises:a tray area for holding collection vessels; and collection bed arms,wherein the collection bed arms extend from the tray area.
 5. Thefraction collector of claim 4 wherein the collection bed arms allowattachment of the collection bed to the support system.
 6. The fractioncollector of claim 1 wherein the collection bed comprises a tray areadesigned to support at least one rack, wherein the at least one rack isdesigned to hold at least one collection vessel.
 7. The fractioncollector of claim 1 wherein the mechanized lift is a screw-driven lift.8. The fraction collector of claim 1 wherein the mechanized lift ismotorized.
 9. The fraction collector of claim 1 wherein the collectionbed further comprises markings used to align the collection bed with thedispensing head.
 10. The fraction collector of claim 1 wherein thecollection bed is attached to the support system.